Physical broadcast channel sending/receiving method, and apparatus

ABSTRACT

This application provides a physical broadcast channel sending/receiving method and an apparatus. In the method, after receiving two broadcast channel signals on two corresponding physical broadcast channels at two time-frequency resource locations, the terminal device determines that information other than an offset of a corresponding time-frequency resource location is the same in two pieces of broadcast information carried in the two broadcast channel signals, obtains a time offset difference between the foregoing two time-frequency resource locations, and generates a scrambling sequence based on the time offset difference; and the terminal device separately descrambles the two broadcast channel signals based on the scrambling sequence and a preset scrambling sequence, thereby implementing joint decoding on the two broadcast channel signals, to obtain one piece of broadcast information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/272,772, filed on Feb. 11, 2019, which is a continuation ofInternational Application No. PCT/CN2017/097226, filed on Aug. 11, 2017,which claims priority to Chinese Patent Application No. 201610666756.9,filed on Aug. 12, 2016. All of the afore-mentioned patent applicationsare hereby incorporated by reference in their entireties.

TECHNICAL FIELD

This application relates to the field of communications technologies,and in particular, to a physical broadcast channel sending/receivingmethod, and an apparatus.

BACKGROUND

With development of communications technologies, a carrier frequencyrange of a wireless access system is also increasingly large. A highcarrier frequency signal fades more seriously in free space. In otherwords, a path loss of the high carrier frequency signal is relativelylarge. Therefore, there is a coverage hole in a cell of a base stationwith a high carrier frequency in the wireless access system.

To meet a coverage requirement, a base station in the wireless accesssystem needs to send a plurality of directional beams at different timesin each sector, to ensure that the plurality of beams can cover theentire sector. A terminal device in the sector may simultaneously detectsignals sent by one base station by using the plurality of beams.

The terminal device accesses a network when determining a frame headerlocation of a radio frame and system information in accurate broadcastinformation. The broadcast information is broadcast by the base stationby using a physical broadcast channel (PBCH), and the system informationis a master information block (MIB).

In the foregoing multi-beam wireless access system, the base stationperiodically sends a corresponding synchronization signal at differenttime-frequency resource locations by using each beam. Apparently, timeoffsets of synchronization signals of different beams are different whenthe synchronization signals of the different beams are sent at differenttimes. A time offset of any synchronization signal is a time offsetbetween a time location at which the base station sends thesynchronization signal in a radio frame and a frame header location ofthe radio frame. To reduce synchronization signal detection complexity,synchronization signals that are transmitted by the base station andthat include different time offsets are the same. After receiving asynchronization signal, the terminal device cannot determine a timeoffset of the synchronization signal, and consequently, cannot determinethe frame header location of the radio frame.

To ensure that the terminal device may determine the frame headerlocation of the radio frame, the base station adds a time offset ofbroadcast information to the broadcast information when sending thebroadcast information. The offset of the broadcast information is a timeoffset between a time location at which the base station sends thebroadcast information in the radio frame and the frame header locationof the radio frame. In this case, when receiving the broadcastinformation, the terminal device may determine the frame header locationof the radio frame based on the time offset of the broadcast informationand a time location at which the broadcast information is received.

There is a problem of uneven coverage in the multi-beam wireless accesssystem. For example, a terminal device at a location A in FIG. 1 mayreceive two pieces of broadcast information sent by the base station byusing a beam 1 and a beam 2. However, the two pieces of broadcastinformation are different because the two pieces of broadcastinformation include different time offset information, and the terminaldevice cannot perform joint decoding on the received two pieces ofbroadcast information to obtain accurate broadcast information.Consequently, the terminal device cannot access the network.

SUMMARY

This application provides a physical broadcast channel sending/receivingmethod and an apparatus, to resolve a prior-art problem that in amulti-beam wireless access system, when receiving broadcast informationof a plurality of beams, a terminal device cannot perform joint decodingto obtain accurate broadcast information, and consequently, the terminaldevice cannot access a network when the terminal device is relativelyfar away from a base station.

Specific technical solutions provided in this application are asfollows:

According to a first aspect, an embodiment of this application providesa physical broadcast channel sending method, where the method is appliedto a multi-beam wireless access system, and includes: sending, by a basestation, at least two physical broadcast channels on at least twotime-frequency resource locations in a radio frame, and sendingindication information for the at least two physical broadcast channels,where one time-frequency resource location is corresponding to onephysical broadcast channel, the physical broadcast channel carriesbroadcast information, the broadcast information includes a time offsetof a time-frequency resource location corresponding to the physicalbroadcast channel, the time offset of the time-frequency resourcelocation corresponding to the physical broadcast channel is informationabout a time interval between a time location of the time-frequencyresource location corresponding to the physical broadcast channel intime domain and a frame header location of the radio frame, theindication information is used to notify a terminal device thatinformation other than time offsets of the time-frequency resourcelocations is the same in broadcast information carried on the at leasttwo physical broadcast channels.

By using the foregoing method, the base station sends the at least twophysical broadcast channels on the at least two time-frequency resourcelocations in the radio frame, and sends the indication information forthe at least two physical broadcast channels. In this case, afterreceiving broadcast channel signals on two physical broadcast channels,the terminal device may determine, based on indication information ofthe two physical broadcast channels, that information other than timeoffsets of time-frequency resource locations is the same in broadcastinformation carried in the two broadcast channel signals, to furtherimplement joint decoding on the two broadcast channel signals, andobtain broadcast information carried in one of the broadcast channelsignals.

In a possible design, the base station sends the indication informationfor the at least two physical broadcast channels in the followingmanner:

The base station sends at least two synchronization signals. Anysynchronization signal is corresponding to at least one of the at leasttwo physical broadcast channels, and synchronization signal sequencescarried in the at least two synchronization signals include theindication information of the at least two physical broadcast channels.

By using the foregoing method, the base station sends indicationinformation of a physical broadcast channel by using a synchronizationsignal, to avoid increasing signaling interaction between the basestation and the terminal device.

In a possible design, the indication information is the synchronizationsignal sequences carried in the at least two synchronization signals.

Using the foregoing method can avoid adding a synchronization signalsequence of the synchronization signal, and avoid increasing overheadsof transmitting the synchronization signal by the base station.

In a possible design, a difference (namely, a time offset differencebetween the foregoing two time-frequency resource locations in timedomain, which is a time difference in essence) between a time offset ofany one of the at least two time-frequency resource locations and a timeoffset of another time-frequency resource location is corresponding toone unique difference sequence.

By using the foregoing method, the terminal device may determine adifference sequence based on the time offset difference of twotime-frequency resource locations in time domain, to further obtain ascrambling sequence based on the difference sequence.

In a possible design, there is a linear relationship between thedifference sequence and bit sequences of the time offsets of theforegoing two time-frequency resource locations. The bit sequences ofthe time offsets of the foregoing two time-frequency resource locationsare bit sequences in broadcast information carried on the physicalbroadcast channels at the foregoing two time-frequency resourcelocations.

In a possible design, the base station sends the at least two physicalbroadcast channels on the at least two time-frequency resource locationsin the following steps:

The base station performs, in a same manner, addition of a cyclicredundancy check CRC code, channel coding, scrambling, and modulation onthe broadcast information carried on the at least two physical broadcastchannels, to generate at least two corresponding broadcast channelsignals. Then the base station sends, on each of the at least twophysical broadcast channels, a broadcast channel signal corresponding tobroadcast information carried on the physical broadcast channel.

By using the foregoing method, the base station may convert thebroadcast information into a broadcast channel signal that may be sentby using a physical broadcast channel.

According to a second aspect, an embodiment of this application providesa physical broadcast channel receiving method, where the method isapplied to a multi-beam wireless access system, and includes thefollowing steps: receiving, by a terminal device, a first broadcastchannel signal on a corresponding first physical broadcast channel at afirst time-frequency resource location in a radio frame, and receiving asecond broadcast channel signal on a corresponding second physicalbroadcast channel at a second time-frequency resource location, wherethe first broadcast channel signal carries first broadcast information,the first broadcast information includes a time offset of the firsttime-frequency resource location, the second broadcast channel signalcarries second broadcast information, the second broadcast informationincludes a time offset of the second time-frequency resource location,and a time offset of any time-frequency resource location is informationabout a time interval between a time location of the time-frequencyresource location in time domain and a frame header location of theradio frame. The method further includes: determining, by the terminaldevice, that first information in the first broadcast information is thesame as second information in the second broadcast information, wherethe first information is information other than the time offset of thefirst time-frequency resource location in the first broadcastinformation, and the second information is information other than thetime offset of the second time-frequency resource location in the secondbroadcast information. The method also includes determining, by theterminal device, a time offset difference between the firsttime-frequency resource location and the second time-frequency resourcelocation in time domain, obtaining a difference sequence correspondingto the time offset difference based on a correspondence between a timeoffset difference and a difference sequence, and generating a scramblingsequence based on the difference sequence, where one time offsetdifference is corresponding to one unique difference sequence in thecorrespondence between a time offset difference and a differencesequence; and descrambling, by the terminal device, the first broadcastchannel signal based on the scrambling sequence, descrambling the secondbroadcast channel signal based on a preset second scrambling sequence ofthe second broadcast channel signal, and performing joint decoding onthe descrambled first broadcast channel signal and the descrambledsecond broadcast channel signal, to obtain the second broadcastinformation.

By using the foregoing method, the terminal device may obtain accuratebroadcast information, determine the frame header location of the radioframe based on a time offset of a time-frequency resource locationincluded in the broadcast information, and access a network based on theobtained accurate frame header location of the radio frame and eachpiece of information (such as system information) carried in thebroadcast information.

In a possible design, the terminal device may determine, in thefollowing two manners, that the first information is the same as thesecond information:

Manner 1: The terminal device obtains indication information of thefirst physical broadcast channel and the second physical broadcastchannel, and determines, based on the indication information, that thefirst information is the same as the second information.

Manner 2: The terminal device determines a first scrambling sequence ofthe first broadcast channel signal and the second scrambling sequence ofthe second broadcast channel signal from a plurality of presetscrambling sequences, and determines, based on the first scramblingsequence and the second scrambling sequence, that the first informationis the same as the second information.

By using the foregoing manners, subsequently the terminal device mayseparately descramble the two broadcast channel signals only afterdetermining that the first information is the same as the secondinformation, and perform joint decoding on the two descrambled broadcastchannel signals, to obtain broadcast information carried in one of thebroadcast channel signals.

In a possible design, the terminal device obtains the indicationinformation by using the following method:

The terminal device receives a first synchronization signalcorresponding to the first physical broadcast channel and a secondsynchronization signal corresponding to the second physical broadcastchannel, and obtains the indication information included insynchronization signal sequences carried in the first synchronizationsignal and the second synchronization signal.

By using the foregoing method, the terminal device receives, by using asynchronization signal, indication information that is of a physicalbroadcast channel and that is sent by a base station, to avoidincreasing signaling interaction between the base station and theterminal device.

In a possible design, the indication information is the synchronizationsignal sequences carried in the first synchronization signal and thesecond synchronization signal.

Using the foregoing method can avoid adding synchronization signalsequences of the foregoing two synchronization signals, and avoidincreasing overheads of transmitting the synchronization signals by thebase station.

In a possible design, when determining that the indication informationis a specified sequence, the terminal device determines that the firstinformation is the same as the second information.

In a possible design, when determining that a synchronization signalsequence carried in the first synchronization signal is the same as asynchronization signal sequence carried in the second synchronizationsignal in the indication information, the terminal device determinesthat the first information is the same as the second information.

In a possible design, that the terminal device determines, based on thefirst scrambling sequence and the second scrambling sequence, that thefirst information is the same as the second information includes: whendetermining that the first scrambling sequence is the same as the secondscrambling sequence, determining, by the terminal device, that the firstinformation is the same as the second information.

In a possible design, the terminal device generates the scramblingsequence based on the difference sequence by using the following step:

The terminal device adds a sequence to the difference sequence, so thata bit sequence length of a difference sequence obtained after thesequence is added is the same as a bit sequence length of the firstbroadcast information carried in the first broadcast channel signal;then performs processing such as addition of a CRC and channel coding onthe difference sequence obtained after the sequence is added, andgenerates the scrambling sequence with reference to the processedsequence and the preset first scrambling sequence of the first broadcastchannel signal.

By using the foregoing method, the terminal device may descramble thefirst broadcast channel signal based on the scrambling sequence, so thatwhen information carried in the descrambled first broadcast channelsignal is the same as information carried in the second broadcastchannel signal descrambled by using the preset second scramblingsequence, joint decoding is implemented to obtain the second broadcastinformation.

In a possible design, after the terminal device obtains the secondbroadcast information, the terminal device obtains the time offset ofthe second time-frequency resource location included in the secondbroadcast information.

The terminal device determines the frame header location of the radioframe based on a time location of the second time-frequency resourcelocation in time domain and the obtained time offset of the secondtime-frequency resource location.

By using the foregoing step, the terminal device may obtain the accurateframe header location of the radio frame, to access the network.

In a possible design, the terminal device determines the frame headerlocation of the radio frame by using the following method:

The terminal device subtracts the time offset of the secondtime-frequency resource location from the time location (a time locationat which the second broadcast channel signal is received) of the secondtime-frequency resource location in time domain, to obtain the frameheader location of the radio frame.

By using the foregoing method, the terminal device may obtain theaccurate frame header location of the radio frame.

According to a third aspect, an embodiment of this application furtherprovides a base station, and the base station has a function ofimplementing base station behavior in the foregoing method designs. Thefunction may be implemented by hardware, or may be implemented byhardware by executing corresponding software. The hardware or thesoftware includes one or more modules corresponding to the foregoingfunction.

In a possible design, a structure of the base station includes aprocessing unit and a sending unit, and the units may performcorresponding functions in the foregoing method designs. For details,refer to detailed descriptions in the method designs. Details are notdescribed herein again.

In a possible design, a structure of the base station includes atransceiver, a processor, a bus, and a memory, the transceiver isconfigured to perform communication interaction with another device in amulti-beam wireless access system, and the processor is configured tosupport the base station in performing a corresponding function in theforegoing method. The memory is coupled to the processor, and the memorystores a program instruction and data that are necessary for the basestation.

According to a fourth aspect, an embodiment of this application furtherprovides a terminal device, and the terminal device has a function ofimplementing terminal device behavior in the foregoing method designs.The function may be implemented by hardware, or may be implemented byhardware by executing corresponding software. The hardware or thesoftware includes one or more modules corresponding to the foregoingfunction.

In a possible design, a structure of the terminal device includes areceiving unit and a processing unit, and the units may performcorresponding functions in the foregoing method designs. For details,refer to detailed descriptions in the method designs. Details are notdescribed herein again.

In a possible design, a structure of the terminal device includes atransceiver, a processor, a bus, and a memory, the transceiver isconfigured to perform communication interaction with another device in amulti-beam wireless access system, and the processor is configured tosupport the terminal device in performing a corresponding function inthe foregoing method. The memory is coupled to the processor, and thememory stores a program instruction and data that are necessary for theterminal device.

According to a fifth aspect, an embodiment of this application providesa multi-beam wireless access system, and the multi-beam wireless accesssystem includes a base station and a terminal device.

By using the physical broadcast channel sending/receiving methodprovided in this application, the base station in the multi-beamwireless access system sends the at least two physical broadcastchannels on the at least two time-frequency resource locations in theradio frame; and the terminal device respectively receives the firstbroadcast channel signal on the corresponding first physical broadcastchannel and the second broadcast channel signal at the firsttime-frequency resource location and the second time-frequency resourcelocation in the at least two time-frequency resource locations. Anybroadcast channel signal carries broadcast information, and thebroadcast information includes a time offset of a correspondingtime-frequency resource location. After determining that the firstinformation (namely, the information other than the time offset of thefirst time-frequency resource location) in the first broadcastinformation is the same as the second information (namely, theinformation other than the time offset of the second time-frequencyresource location) in the second broadcast information, the terminaldevice determines the time offset difference between the foregoing twotime-frequency resource locations, and generates the scrambling sequencebased on the time offset difference. The terminal device may descramblethe first broadcast channel signal based on the scrambling sequence, andimplement joint decoding on the descrambled first broadcast channelsignal and the second broadcast channel signal descrambled based on thepreset second scrambling sequence, to obtain the second broadcastinformation. In this case, the terminal device may obtain accuratebroadcast information, may determine the frame header location of theradio frame based on a time offset of a time-frequency resource locationincluded in the broadcast information, and access a network based on theobtained accurate frame header location of the radio frame and eachpiece of information (such as system information) carried in thebroadcast information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of broadcast information transmissionaccording to the prior art;

FIG. 2 is an architectural diagram of a multi-beam wireless accesssystem according to an embodiment of this application;

FIG. 3 is a flowchart of a physical broadcast channel sending methodaccording to an embodiment of this application;

FIG. 4 is a schematic diagram of sending a physical broadcast channel bya base station according to an embodiment of this application;

FIG. 5 is a flowchart of a physical broadcast channel receiving methodaccording to an embodiment of this application;

FIG. 6 is a schematic diagram of a procedure in which a terminal deviceobtains second broadcast information based on a difference sequenceaccording to an embodiment of this application;

FIG. 7A and FIG. 7B are an example diagram of a physical broadcastchannel transmission method according to an embodiment of thisapplication;

FIG. 8A and FIG. 8B are an example diagram of another physical broadcastchannel transmission method according to an embodiment of thisapplication;

FIG. 9 is a structural diagram of a base station according to anembodiment of this application;

FIG. 10 is a structural diagram of a terminal device according to anembodiment of this application;

FIG. 11 is a structural diagram of another base station according to anembodiment of this application; and

FIG. 12 is a structural diagram of another terminal device according toan embodiment of this application.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

To make the objectives, technical solutions, and advantages of thisapplication clearer, the following further describes this application indetail with reference to the accompanying drawings. Apparently, thedescribed embodiments are merely some rather than all of the embodimentsof this application. All other embodiments obtained by persons ofordinary skill in the art based on the embodiments of this applicationwithout creative efforts shall fall within the protection scope of thisapplication.

Embodiments of this application provide a physical broadcast channelsending/receiving method and an apparatus, to resolve a prior-artproblem that in a multi-beam wireless access system, when receivingbroadcast information of a plurality of beams, a terminal device cannotperform joint decoding to obtain accurate broadcast information, andconsequently, the terminal device cannot access a network when theterminal device is relatively far away from a base station. The methodand the apparatus in this application are based on a same inventiveconcept. Because the method and the apparatus have a similar principlefor resolving the problem, mutual reference may be made betweenapparatus implementation and method implementation. No repeateddescription is provided.

In the embodiments of this application, a base station in a multi-beamwireless access system sends at least two physical broadcast channels onat least two time-frequency resource locations in a radio frame, and aterminal device respectively receives a first broadcast channel signalon a corresponding first physical broadcast channel and a secondbroadcast channel signal at a first time-frequency resource location anda second time-frequency resource location in the at least twotime-frequency resource locations. Any broadcast channel signal carriesbroadcast information, and the broadcast information includes a timeoffset of a corresponding time-frequency resource location. Afterdetermining that first information (namely, information other than atime offset of the first time-frequency resource location) in firstbroadcast information is the same as second information (namely,information other than a time offset of the second time-frequencyresource location) in second broadcast information, the terminal devicedetermines a time offset difference between the foregoing twotime-frequency resource locations, and generates a scrambling sequencebased on the time offset difference. The terminal device may descramblethe first broadcast channel signal based on the scrambling sequence, andimplement joint decoding on the descrambled first broadcast channelsignal and the second broadcast channel signal descrambled based on apreset second scrambling sequence, to obtain the second broadcastinformation. In this case, the terminal device may obtain accuratebroadcast information, may determine a frame header location of theradio frame based on a time offset of a time-frequency resource locationincluded in the broadcast information, and access a network based on theobtained accurate frame header location of the radio frame and eachpiece of information (such as system information) carried in thebroadcast information.

The following explains some terms in this application to facilitateunderstanding by persons skilled in the art.

(1) The base station in the embodiments of this application is a devicethat connects the terminal device to a wireless network. The basestation has a relatively large carrier frequency range, and the basestation includes an antenna array including a large quantity of antennaarray elements. The base station may generate a plurality ofhigh-directivity beams (directional beams) by using the antenna array,to obtain an antenna array gain. The base station may include but is notlimited to an evolved Node B (eNB), a radio network controller (RNC), aNode B (NodeB, NB), a base station controller (BSC), a base transceiverstation (BTS), a home eNodeB (home evolved NodeB or Home NodeB, HNB), abaseband unit (BBU), and an access point (AP).

(2) The terminal device in the embodiments of this application is alsoreferred to as user equipment (UE), and is a device that provides a userwith voice and/or data connectivity, for example, a handheld device, amobile phone, an in-vehicle device, a wearable device, a computingdevice, or a mobile station (MS) that has a wireless connectionfunction, or another processing device connected to a wireless modem.

(3) The time offset of the time-frequency resource location in the radioframe in the embodiments of this application is information about a timeinterval between a time location of the time-frequency resource locationin time domain and the frame header location of the radio frame. Aphysical expression manner of the time offset may be an absolute time (aunit is second, millisecond, microsecond, or the like), or may be aphysical quantity that may represent a time interval, for example, aquantity of subframes, or a quantity of symbols (for example, orthogonalfrequency division multiplexing (OFDM) symbols). This is not limited inthis application. For example, an absolute time offset of a start timelocation that is of a time-frequency resource location corresponding toa physical broadcast channel in time domain and that is relative to theframe header location of the radio frame is two subframes and four OFDMsymbols. The information about the time interval includes a valueobtained by rounding down the absolute time offset, and the informationabout the time interval is two subframes in the foregoing case.

(4) “A plurality of” in the embodiments of this application means two ormore.

(5) “And/or” in the embodiments of this application is used to describean association relationship of associated objects, and indicates thatthree relationships may exist. For example, A and/or B may represent thefollowing three cases: Only A exists, both A and B exist, and only Bexists. The character “/” generally indicates an “or” relationshipbetween the associated objects.

In addition, it should be understood that, in the description of thisapplication, terms “first” and “second” are only used for a purpose ofdistinguishing between descriptions, but cannot be understood as anindication or implication of relative importance, and cannot beunderstood as an indication or implication of a sequence.

To more clearly describe the technical solutions in the embodiments ofthis application, with reference to FIG. 2 , the following describes apossible multi-beam wireless access system in the embodiments of thisapplication. FIG. 2 shows an architecture of a possible multi-beamwireless access system according to an embodiment of this application.The multi-beam wireless access system includes a base station 201 and aterminal device 202.

The base station 201 may generate a plurality of high-gain directionalbeams by using an antenna array of the base station 201. Optionally, thebase station 201 may send a plurality of beams in each sector of thebase station 201. The base station 201 may send a physical broadcastchannel on a time-frequency resource location of a radio frame and byusing each beam. The physical broadcast channel carries broadcastinformation, and the broadcast information includes system informationsuch as a MIB. To ensure that the terminal device may determine a frameheader location of the radio frame, the broadcast information furtherincludes a time offset of the time-frequency resource location.

The terminal device 202 is configured to: receive a broadcast channelsignal on the physical broadcast channel sent by the base station, andobtain broadcast information in the broadcast channel signal. Theterminal device 202 determines the frame header location of the radioframe based on the time offset of the time-frequency resource locationin the broadcast information, and finally accesses a network based onthe frame header location of the radio frame and the system informationincluded in the broadcast information.

As shown in FIG. 2 , there is a problem of uneven coverage in themulti-beam wireless access system. Therefore, in actual application,there are two physical broadcast channel receiving cases for theterminal device 202.

Case 1: The terminal device is located at a strong coverage location ofa beam (a beam 1), for example, a location A in the figure.

The terminal device 202 receives a broadcast channel signal on aphysical broadcast channel at a time-frequency resource location of thebeam 1 of the radio frame, and the physical broadcast channel is sent bythe base station 201 by using the beam 1.

After performing processing such as demodulation, descrambling, anddecoding on the broadcast channel signal, the terminal device 202 maydirectly obtain broadcast information 1 carried in the broadcast channelsignal.

The terminal device 202 may obtain a time offset of the time-frequencyresource location included in the broadcast information 1, and obtainthe frame header location of the radio frame based on a time location (atime location at which the terminal device 202 receives the physicalbroadcast channel) of the time-frequency resource location in timedomain and the time offset of the time-frequency resource location.

Finally, the terminal device 202 may access the network based on theframe header location of the radio frame and system information includedin the broadcast information 1.

Case 2: The terminal device is located in a weak coverage location oftwo beams (a beam 1 and a beam 2), for example, a location B in thefigure. In this case, after performing processing such as demodulation,descrambling, and decoding on the broadcast information in the case 1,the terminal device cannot obtain accurate broadcast information carriedin the broadcast channel signal.

The terminal device 202 receives a broadcast channel signal 1 on acorresponding physical broadcast channel 1 at a time-frequency resourcelocation 1 of the radio frame, and the physical broadcast channel 1 issent by the base station 201 by using the beam 1.

The terminal device 202 receives a broadcast channel signal 2 on acorresponding physical broadcast channel 2 at a time-frequency resourcelocation 2 of the radio frame, and the physical broadcast channel 2 issent by the base station 201 by using the beam 2.

When the terminal device 202 determines that information other thancorresponding time-frequency resource locations is the same in broadcastinformation 1 and broadcast information 2 that are respectively carriedin the broadcast channel signal 1 and the broadcast channel signal 2,the terminal device generates a scrambling sequence of the broadcastchannel signal 1 and/or a scrambling sequence of the broadcast channelsignal 2. Details are as follows.

The terminal device 202 determines a time offset difference between thetime-frequency resource location 1 and the time-frequency resourcelocation 2, and determines a difference sequence corresponding to thetime offset difference based on a stored correspondence between a timeoffset difference (a time difference) and a difference sequence.

The terminal device 202 generates a scrambling sequence based on thedifference sequence.

The terminal device 202 descrambles the broadcast channel signal 1, anddescrambles the broadcast channel signal 2 by using a preset scramblingsequence.

The terminal device 202 performs joint decoding on the two descrambledbroadcast channel signals, to generate the broadcast information 2.

The terminal device 202 may obtain a time offset of the time-frequencyresource location 2 included in the broadcast information 2, and obtainthe frame header location of the radio frame based on a time location (atime location at which the terminal device 202 receives the physicalbroadcast channel 2) of the time-frequency resource location 2 in timedomain and the time offset of the time-frequency resource location 2.

Finally, the terminal device 202 may access the network based on theframe header location of the radio frame and system information includedin the broadcast information 2.

The terminal device 202 may generate the broadcast information 1 basedon a same principle. For a specific method step, refer to the foregoingsteps. Details are not described herein again.

By using the foregoing steps, the terminal device 202 may separatelydescramble two broadcast channel signals when the time offsets of thetime-frequency resource locations carried in the two broadcast channelsignals are different, and other information is the same, to implementjoint decoding on the two broadcast channel signals, obtain systeminformation and a time offset of a time-frequency resource location inany of the broadcast channel signals, and obtain the frame headerlocation of the radio frame based on the obtained time offset of thetime-frequency resource location. Finally, the terminal device 202 mayaccess the network based on the frame header location of the radio frameand the obtained system information in the broadcast information.

Referring to FIG. 3 , an embodiment of this application provides aphysical broadcast channel sending method, and the method is applied tothe multi-beam wireless access system shown in FIG. 2 . A processingprocedure of the method includes the following steps.

Step 301: A base station sends at least two physical broadcast channelson at least two time-frequency resource locations in a radio frame,where one time-frequency resource location is corresponding to onephysical broadcast channel, the physical broadcast channel carriesbroadcast information, the broadcast information includes a time offsetof a time-frequency resource location corresponding to the physicalbroadcast channel, the time offset of the time-frequency resourcelocation corresponding to the physical broadcast channel is informationabout a time interval between a time location of the time-frequencyresource location corresponding to the physical broadcast channel intime domain and a frame header location of the radio frame, and timeoffsets of the time-frequency resource locations included in broadcastinformation carried on the at least two physical broadcast channels aredifferent.

Because the base station sends a physical broadcast channel by using abeam, a quantity of physical broadcast channels sent by the base stationis the same as a quantity of beams generated by the base station.Because time-frequency resource locations are in a one-to-onecorrespondence with physical broadcast channels, a quantity of physicalbroadcast channels sent by the base station is the same as a quantity oftime-frequency resource locations in one radio frame that are occupiedwhen the base station sends the physical broadcast channels.

For example, when a plurality of beams generated by the base stationinclude a first beam and a second beam, referring to FIG. 4 , the basestation sends a physical broadcast channel at a first time-frequencyresource location by using the first beam, and the base station sends aphysical broadcast channel at a second time-frequency resource locationby using the second beam.

A terminal device cannot determine the frame header location of theradio frame based on a received synchronization signal. To ensure thatthe terminal device may accurately determine the frame header locationof the radio frame, broadcast information carried on each physicalbroadcast channel sent by the base station includes a time offset of atime-frequency resource location occupied by the physical broadcastchannel. In this case, after receiving a broadcast channel signal of aphysical broadcast channel, the terminal device may determine the frameheader location of the radio frame by using a time offset of atime-frequency resource location occupied by the physical broadcastchannel. FIG. 4 is still used as an example. Broadcast informationcarried on the physical broadcast channel sent by the base station atthe first time-frequency resource location includes a time offset of thefirst time-frequency resource location.

Conventional broadcast information includes system information, and abit sequence length of the conventional broadcast information is L. Inthis embodiment of this application, the broadcast information includesthe time offset of the time-frequency resource location. Therefore, abit sequence length of the broadcast information is L+M, and M is a bitsequence length of the time offset of the time-frequency resourcelocation.

Optionally, in the broadcast information, a bit sequence of the timeoffset of the time-frequency resource location may be at a startlocation or an end location of the bit sequence of the broadcastinformation, or at a specified location of a bit sequence of thebroadcast information. This is not limited in this application.

Specifically, when the base station performs step 301, the followingsteps are included:

The base station performs addition of a cyclic redundancy check (CRC)code, channel coding, scrambling, and modulation in a same manner on thebroadcast information carried on the at least two physical broadcastchannels, to generate at least two corresponding broadcast channelsignals.

The base station sends, on each of the at least two physical broadcastchannels, a broadcast channel signal corresponding to broadcastinformation carried on the physical broadcast channel.

An implementation in which the base station adds the CRC includes:adding, to an existing bit sequence whose length is L, K check bits usedto check the bit sequence, and finally generating a bit sequence whoselength is L+M+K. The K check bits are generated based on the bitsequence whose length is L.

An implementation in which the base station performs channel codingincludes a tail biting convolutional code in a Long Term Evolution (LTE)technology.

An implementation in which the base station performs modulation includesquadrature phase shift keying (QPSK) modulation.

The base station scrambles a plurality of pieces of broadcastinformation by using a plurality of preset scrambling sequences.

Step 302: The base station sends indication information for the at leasttwo physical broadcast channels, where the indication information isused to notify a terminal device that information other than the timeoffsets of the time-frequency resource locations is the same in thebroadcast information carried on the at least two physical broadcastchannels.

The indication information may be further used to notify the terminaldevice that information other than time offsets of time-frequencyresource locations is different in broadcast information carried onreceived two physical broadcast channels.

The physical broadcast channels are in a one-to-one correspondence withthe time-frequency resource locations. Therefore, when the base stationsends a plurality of physical broadcast channels, time offsets oftime-frequency resource locations in broadcast information carried onany two physical broadcast channels are different. However, information(such as system information) other than time offsets may be the same inbroadcast information carried on some of the physical broadcastchannels.

When broadcast information carried on two physical broadcast channels islocated in a same time unit, information other than time offsets is thesame in the broadcast information carried on the two physical broadcastchannels. For example, the broadcast information includes informationrelated to the radio frame, and the information related to the radioframe remains unchanged in a period of 40 ms. However, the informationrelated to the radio frame changes at an interval of 40 ms. In thiscase, information other than time offsets in broadcast information inone time unit (a period of 40 ms) is the same, and information otherthan time offsets in broadcast information in different time units isdifferent.

The terminal device may receive broadcast channel signals of a pluralityof physical broadcast channels at a weak coverage location. To obtainaccurate broadcast information, the terminal device needs to performjoint decoding (to be specific, perform soft combination processing onthe plurality of broadcast channel signals) on broadcast channel signalscarrying broadcast information including same information. For example,joint decoding may be implemented by using a chase combining method oranother method. A joint decoding method is not limited in thisembodiment of this application. It may be obtained from the foregoingdescription that, to ensure that after receiving the broadcast channelsignals of the plurality of physical broadcast channels, the terminaldevice at the weak coverage location may perform joint decoding on theplurality of received broadcast channel signals, to obtain accuratebroadcast information carried in one of the broadcast channel signals,the terminal device needs to determine that broadcast informationcarried in the plurality of received broadcast channel signals includessame information. Optionally, the terminal device determines theforegoing case by using the indication information of the physicalbroadcast channels that is sent by the base station.

Optionally, that the base station sends indication information for theat least two physical broadcast channels includes:

sending, by the base station, at least two synchronization signals,where any synchronization signal is corresponding to at least one of theat least two physical broadcast channels, and synchronization signalsequences carried in the at least two synchronization signals includethe indication information of the at least two physical broadcastchannels.

FIG. 4 is still used as an example. Indication information of thephysical broadcast channel sent by using the first beam and indicationinformation of the physical broadcast channel sent by using the secondbeam may be included in a synchronization sequence sent by using thefirst beam and/or a synchronization sequence sent by using the secondbeam.

By using the foregoing method, the base station sends indicationinformation of a physical broadcast channel by using a synchronizationsignal, to avoid increasing signaling interaction between the basestation and the terminal device.

Optionally, the indication information is synchronization signalsequences carried in the at least two synchronization signals.

Using the foregoing manner can avoid adding a synchronization signalsequence of the synchronization signal, and avoid increasing overheadsof transmitting the synchronization signal by the base station.

When synchronization signal sequences of synchronization signals of twophysical broadcast channels sent by the base station are the same,indication information (namely, the synchronization signal sequences ofthe two synchronization signals) of the two physical broadcast channelsmay be used to notify the terminal device that information other thantime offsets of time-frequency resource locations is the same inbroadcast information carried in broadcast channel signals on the twophysical broadcast channels. Because the foregoing two synchronizationsignals further include information indicating a serving cell identifierof the terminal device, information about serving cell identifierscarried in the foregoing two synchronization signals is also the same.

Optionally, a difference (namely, a time offset difference between theforegoing two time-frequency resource locations in time domain, which isa time difference in essence) between a time offset of any one of the atleast two time-frequency resource locations and a time offset of anothertime-frequency resource location is corresponding to one uniquedifference sequence. However, a same difference sequence may becorresponding to one or more time differences.

For example, a difference (a time difference) between a time offset of atime-frequency resource location 1 and a time offset of a time-frequencyresource location 2 includes the following possible cases: {onesubframe, two subframes, three subframes}.

When different time differences each are corresponding to a uniquedifference sequence, a correspondence between a time difference and adifference sequence is shown in Table 1.

TABLE 1 Correspondence between a time difference and a differencesequence Time difference Difference sequence One subframe {01} Twosubframes {10} Three subframes {11}

When a same difference sequence may be corresponding to a plurality oftime differences, a correspondence between a time difference and adifference sequence is shown in Table 2.

TABLE 2 Correspondence between a time difference and a differencesequence Time difference Difference sequence One subframe {01} Twosubframes {01} Three subframes {11}

Optionally, there is a linear relationship between the differencesequence and bit sequences of the time offsets of the foregoing twotime-frequency resource locations. The bit sequences of the time offsetsof the foregoing two time-frequency resource locations are bit sequencesin broadcast information carried on the physical broadcast channels atthe foregoing two time-frequency resource locations.

The difference sequence is used to generate a scrambling sequence. Whenthe terminal device determines that information other than time offsetsof time-frequency resource locations is the same in first broadcastinformation carried in a received first broadcast channel signal andsecond broadcast information carried in a received second broadcastchannel signal, the terminal device may determine a difference sequenceby using a time offset difference between a first time-frequencyresource location at which the first broadcast channel signal isreceived and a second time-frequency resource location at which thesecond broadcast channel signal is received in time domain, and obtain ascrambling sequence by using the difference sequence. Finally, theterminal device may descramble the first broadcast channel signal, sothat information carried in the descrambled first broadcast channelsignal is the same as information carried in the second broadcastchannel signal descrambled by using a preset second scrambling sequence,to implement joint decoding, and obtain the second broadcastinformation.

It can be learned from the foregoing description that the terminaldevice maintains a correspondence between a time difference and adifference sequence, so that a corresponding difference sequence may beobtained based on a time offset difference between two time-frequencyresource locations in time domain, and a scrambling sequence may beobtained.

By using the physical broadcast channel sending method in the foregoingembodiment of this application, the base station sends the at least twophysical broadcast channels on the at least two time-frequency resourcelocations in the radio frame, and sends the indication information forthe at least two physical broadcast channels. In this case, afterreceiving broadcast channel signals on two physical broadcast channels,the terminal device may determine, based on indication information ofthe two physical broadcast channels, that information other than timeoffsets of time-frequency resource locations is the same in broadcastinformation carried in the two broadcast channel signals, to furtherimplement joint decoding on the two broadcast channel signals, andobtain broadcast information carried in one of the broadcast channelsignals.

This application further provides a physical broadcast channel receivingmethod, and the method is applied to the multi-beam wireless accesssystem shown in FIG. 2 . A terminal device is in a weak coveragelocation (a location B in FIG. 2 ). Referring to FIG. 5 , a processingprocedure of the method includes the following steps.

Step 501: The terminal device receives a first broadcast channel signalon a corresponding first physical broadcast channel at a firsttime-frequency resource location in a radio frame, and receives a secondbroadcast channel signal on a corresponding second physical broadcastchannel at a second time-frequency resource location, where the firstbroadcast channel signal carries first broadcast information, the firstbroadcast information includes a time offset of the first time-frequencyresource location, the second broadcast channel signal carries secondbroadcast information, the second broadcast information includes a timeoffset of the second time-frequency resource location, and a time offsetof any time-frequency resource location is information about a timeinterval between a time location of the time-frequency resource locationin time domain and a frame header location of the radio frame.

Because the terminal device is in the weak coverage location, when abase station sends a plurality of physical broadcast channels on aplurality of time-frequency resource locations in the radio frame, theterminal device may receive broadcast channel signals of the pluralityof physical broadcast channels sent by the base station. In thisembodiment of this application, an example in which the terminal devicereceives broadcast channel signals of two physical broadcast channels isonly used for description.

Step 502: The terminal device determines that first information in thefirst broadcast information is the same as second information in thesecond broadcast information, where the first information is informationother than the time offset of the first time-frequency resource locationin the first broadcast information, and the second information isinformation other than the time offset of the second time-frequencyresource location in the second broadcast information.

After performing step 502, the terminal device may separately descramblethe two broadcast channel signals subsequently, and perform jointdecoding on the two descrambled broadcast channel signals, to obtainbroadcast information carried in one of the broadcast channel signals.

Optionally, the terminal device may determine, in the following twomanners, that the first information is the same as the secondinformation:

Manner 1: When the base station in the multi-beam wireless access systemsends indication information for the first physical broadcast channeland the second physical broadcast channel by using the method in thisembodiment shown in FIG. 3 , the terminal device obtains the indicationinformation of the first physical broadcast channel and the secondphysical broadcast channel, and determines, based on the indicationinformation, that the first information is the same as the secondinformation.

Manner 2: When the base station in the multi-beam wireless access systemindicates, by using a preset scrambling sequence used to scramble thefirst physical broadcast channel and the second physical broadcastchannel, that the first information is the same as the secondinformation, the terminal device determines a first scrambling sequenceof the first broadcast channel signal and a second scrambling sequenceof the second broadcast channel signal from a plurality of presetscrambling sequences, and determines, based on the first scramblingsequence and the second scrambling sequence, that the first informationis the same as the second information. The plurality of presetscrambling sequences stored by the terminal device are scramblingsequences used by the base station to scramble the plurality of physicalbroadcast channels.

Optionally, the base station notifies the terminal device when the basestation uses one of the foregoing indication manners (performsindication by using a synchronization signal or by using a scramblingsequence), so that the terminal device may determine, in the foregoingcorresponding manners, that the first information is the same as thesecond information.

Optionally, in the manner 1, that the terminal device obtains theindication information includes: receiving, by the terminal device, afirst synchronization signal corresponding to the first physicalbroadcast channel and a second synchronization signal corresponding tothe second physical broadcast channel, and obtaining the indicationinformation included in synchronization signal sequences carried in thefirst synchronization signal and the second synchronization signal.

Optionally, that the terminal device determines, based on the indicationinformation, that the first information is the same as the secondinformation includes: when determining that the indication informationis a specified sequence, determining, by the terminal device, that thefirst information is the same as the second information.

Optionally, the indication information is the synchronization signalsequences carried in the first synchronization signal and the secondsynchronization signal; and that the terminal device determines, basedon the indication information, that the first information is the same asthe second information includes: when determining that a synchronizationsignal sequence carried in the first synchronization signal is the sameas a synchronization signal sequence carried in the secondsynchronization signal in the indication information, determining, bythe terminal device, that the first information is the same as thesecond information.

Optionally, in the manner 2, that the terminal device determines, basedon the first scrambling sequence and the second scrambling sequence,that the first information is the same as the second informationincludes: when determining that the first scrambling sequence is thesame as the second scrambling sequence, determining, by the terminaldevice, that the first information is the same as the secondinformation.

It should be noted that an execution sequence of step 502 and step 501is not limited in this embodiment of this application. For example, whenthe terminal device determines, in the manner 1, that the firstinformation is the same as the second information, because the terminaldevice first receives a synchronization signal and then receives abroadcast channel signal on a physical broadcast channel (as shown inFIG. 4 ), the terminal device may perform step 502 before step 501. Whenthe terminal device determines, in the manner 2, that the firstinformation is the same as the second information, the terminal devicemay perform step 501 before step 502.

Step 503: The terminal device determines a time offset differencebetween the first time-frequency resource location and the secondtime-frequency resource location in time domain, obtains a differencesequence corresponding to the time offset difference, and generates ascrambling sequence based on the difference sequence, where one timeoffset difference is corresponding to one unique difference sequence.

It can be learned from the description of the difference sequence in theembodiment shown in FIG. 3 that the terminal device maintains acorrespondence between a time difference (which may also be referred toas a time offset difference) and a difference sequence, so that afterthe time offset difference between the first time-frequency resourcelocation and the second time-frequency resource location in time domainis obtained, the difference sequence corresponding to the time offsetdifference may be obtained based on the correspondence between a timedifference and a difference sequence, to generate the scramblingsequence.

Because there is a linear relationship between the difference sequenceand the following two: a bit sequence of the time offset of the firsttime-frequency resource location in the first broadcast information anda bit sequence of the time offset of the second time-frequency resourcelocation in the second broadcast information, optionally, a bit sequencelength of the difference sequence is the same as a bit sequence lengthof the time offset of the first/second time-frequency resource location.Therefore, to ensure that the generated scrambling sequence may be usedto descramble the first broadcast channel signal, the terminal deviceneeds to add a sequence to the difference sequence, and a bit sequencelength of the generated scrambling sequence is equal to a bit sequencelength of the first broadcast information. Optionally, a location of theadded sequence is determined based on a location of the bit sequence ofthe time offset of the first time-frequency resource location in a bitsequence of the first broadcast information. In conclusion, it needs tobe ensured that a location of the original difference sequence in adifference sequence obtained after the sequence is added is the same asthe location of the bit sequence of the time offset of the firsttime-frequency resource location in the bit sequence of the firstbroadcast information.

Optionally, a bit value of each added sequence is fixed, to be specific,is 0 or 1.

After generating the difference sequence (referred to as a firstsequence) obtained after the sequence is added, the terminal deviceperforms processing such as addition of a CRC and channel coding on thefirst sequence, and generates the scrambling sequence with reference tothe processed first sequence and the preset first scrambling sequence ofthe first broadcast channel signal.

Step 504: The terminal device descrambles the first broadcast channelsignal based on the scrambling sequence, descrambles the secondbroadcast channel signal based on a preset second scrambling sequence ofthe second broadcast channel signal, and performs joint decoding on thedescrambled first broadcast channel signal and the descrambled secondbroadcast channel signal, to obtain the second broadcast information.

By using step 504, the terminal device may obtain the accurate secondbroadcast information, to ensure that the terminal device maysubsequently obtain the time offset of the second time-frequencyresource location included in the second broadcast information, andfinally determine the frame header location of the radio frame based onthe time offset of the second time-frequency resource location.

A specific procedure of performing step 503 and step 504 by the terminaldevice is shown in FIG. 6 .

Optionally, after step 504, the terminal device obtains the time offsetof the second time-frequency resource location included in the secondbroadcast information; and the terminal device determines the frameheader location of the radio frame based on a time location of thesecond time-frequency resource location in time domain and the obtainedtime offset of the second time-frequency resource location.

That the terminal device determines the frame header location of theradio frame includes:

subtracting, by the terminal device, the time offset of the secondtime-frequency resource location from the time location (a time locationat which the second broadcast channel signal is received) of the secondtime-frequency resource location in time domain, to obtain the frameheader location of the radio frame.

By using the foregoing step, the terminal device may obtain the accurateframe header location of the radio frame, to access a network.

By using the physical broadcast channel receiving method provided inthis embodiment of this application, the terminal device respectivelyreceives the first broadcast channel signal on the corresponding firstphysical broadcast channel and the second broadcast channel signal atthe first time-frequency resource location and the second time-frequencyresource location in the at least two time-frequency resource locations.Any broadcast channel signal carries broadcast information, and thebroadcast information includes a time offset of a correspondingtime-frequency resource location. After determining that the firstinformation (namely, the information other than the time offset of thefirst time-frequency resource location) in the first broadcastinformation is the same as the second information (namely, theinformation other than the time offset of the second time-frequencyresource location) in the second broadcast information, the terminaldevice determines the time offset difference between the foregoing twotime-frequency resource locations, and generates the scrambling sequencebased on the time offset difference. The terminal device may descramblethe first broadcast channel signal based on the scrambling sequence, andimplement joint decoding on the descrambled first broadcast channelsignal and the second broadcast channel signal descrambled based on thepreset second scrambling sequence, to obtain the second broadcastinformation. In this case, the terminal device may obtain accuratebroadcast information, may determine the frame header location of theradio frame based on a time offset of a time-frequency resource locationincluded in the broadcast information, and access the network based onthe obtained accurate frame header location of the radio frame and eachpiece of information (such as system information) carried in thebroadcast information.

Based on the foregoing embodiments, this application further provides anexample of a physical broadcast channel transmission method, and theexample is applicable to the multi-beam wireless access system shown inFIG. 2 . In this example, the terminal device indicates, by using asynchronization signal sent by a base station, that information otherthan time offsets of time-frequency resource locations is the same inbroadcast information carried on at least two physical broadcastchannels. Referring to FIG. 7A and FIG. 7B, a specific procedureincludes the following steps.

Step 701: The base station sends, on a plurality of time-frequencyresource locations in a radio frame, a plurality of synchronizationsignals corresponding to a plurality of physical broadcast channels,where synchronization signal sequences carried in the plurality ofsynchronization signals are indication information of the plurality ofphysical broadcast channels.

The synchronization signals are in a one-to-one correspondence with thephysical broadcast channels. The indication information is used tonotify the terminal device that when broadcast channel signals of atleast two physical broadcast channels are received, whether informationother than time offsets of time-frequency resource locations is the samein broadcast information carried in the at least two broadcast channelsignals.

Synchronization signal sequences carried in synchronization signals in aspecified time unit are the same, and synchronization signal sequencescarried in synchronization signals in two adjacent time units aredifferent. The time unit may be at least one subframe or at least oneradio frame. For example, when the time unit is one radio frame, asynchronization signal sequence carried in a synchronization signal inan odd numbered time unit is a first synchronization signal sequence,and a synchronization signal sequence carried in a synchronizationsignal in an even numbered time unit is a second synchronization signalsequence. Therefore, a synchronization signal sequence carried in asynchronization signal may indicate whether a current time unit is anodd numbered time unit or an even numbered time unit. Thesynchronization signal sequences carried in the synchronization signalsin the specified time unit are the same, and indicate that informationother than time offsets of time-frequency resource locations in any twopieces of broadcast information in the odd numbered time unit or theeven numbered time unit is the same.

Step 702: The terminal device receives a first synchronization signalcorresponding to a first physical broadcast channel and a secondsynchronization signal corresponding to a second physical broadcastchannel in the plurality of synchronization signals, determines thatsynchronization signal sequences carried in the first synchronizationsignal and the second synchronization signal are indication informationof the first physical broadcast channel and the second physicalbroadcast channel, and determines, based on the indication information,that first information in first broadcast information is the same assecond information in second broadcast information.

The first broadcast information is carried in a first broadcast channelsignal of the first physical broadcast channel, and the second broadcastinformation is carried in a second broadcast channel signal of thesecond physical broadcast channel.

The first information is information other than a time offset of a firsttime-frequency resource location occupied by the first physicalbroadcast channel in the first broadcast information, and the secondinformation is information other than a time offset of a secondtime-frequency resource location occupied by the second physicalbroadcast channel in the second broadcast information.

The determining, based on the indication information, that firstinformation in first broadcast information is the same as secondinformation in second broadcast information includes: when determiningthat a synchronization signal sequence carried in the firstsynchronization signal is the same as a synchronization signal sequencecarried in the second synchronization signal in the indicationinformation, determining, by the terminal device, that the firstinformation is the same as the second information.

The terminal device determines, based on the synchronization signalsequences, whether a time-frequency resource location corresponding tothe received first physical broadcast channel and a time-frequencyresource location corresponding to the received second physicalbroadcast channel are located in a same time unit. If determining, basedon the synchronization signal sequences, that the first physicalbroadcast channel and the second physical broadcast channel are locatedin a same time unit, the terminal device may determine that the firstinformation is the same as the second information.

In this example, an execution sequence of step 702 is not limited, andit only needs to ensure that step 702 is performed after step 701 andbefore step 705.

Step 703: The base station performs addition of a CRC, channel coding,scrambling, and modulation on a plurality of pieces of broadcastinformation in a same manner, to generate a plurality of correspondingbroadcast channel signals.

The base station scrambles the plurality of pieces of broadcastinformation by using a plurality of preset scrambling sequences, andsends the plurality of preset scrambling sequences to the terminaldevice.

Step 704: The base station sends the plurality of pieces of broadcastinformation on the plurality of time-frequency resource locations in theradio frame and by using the plurality of physical broadcast channels(in other words, the base station sends the plurality of physicalbroadcast channels). Each piece of broadcast information carriescorresponding broadcast information.

Step 705: After receiving a first broadcast channel signal on thecorresponding first physical broadcast channel at a first time-frequencyresource location in the plurality of time-frequency resource locations,and receiving a second broadcast channel signal on the correspondingsecond physical broadcast channel at a second time-frequency resourcelocation, the terminal device determines a time offset differencebetween the first time-frequency resource location occupied by the firstphysical broadcast channel and the second time-frequency resourcelocation in time domain, obtains a difference sequence corresponding tothe time offset difference, and generates a scrambling sequence based onthe difference sequence.

The terminal device maintains a correspondence between a time differenceand a difference sequence. Therefore, after obtaining the time offsetdifference, the terminal device may obtain, based on the correspondencebetween a time difference and a difference sequence, the differencesequence corresponding to the time offset difference, to generate thescrambling sequence.

In this example, for a specific process in which the terminal devicegenerates the scrambling sequence based on the difference sequence,refer to the foregoing embodiment. Details are not described hereinagain.

Step 706: The terminal device descrambles the received first broadcastchannel signal based on the scrambling sequence, and descrambles thesecond broadcast channel signal based on a preset second scramblingsequence of the second broadcast channel signal.

The second scrambling sequence is sent by the base station to theterminal device.

In step 706, the terminal device descrambles the first broadcast channelsignal, so that when information carried in the descrambled firstbroadcast channel signal is the same as information carried in thesecond broadcast channel signal descrambled by using the preset secondscrambling sequence, joint decoding is implemented to obtain the secondbroadcast information.

Step 707: The terminal device performs joint decoding on the descrambledfirst broadcast channel signal and the descrambled second broadcastchannel signal, to obtain the second broadcast information.

Step 708: The terminal device obtains a time offset of the secondtime-frequency resource location included in the second broadcastinformation, and determines a frame header location of the radio framebased on a time location of the second time-frequency resource locationin time domain and the time offset of the second time-frequency resourcelocation.

The terminal device subtracts the time offset of the secondtime-frequency resource location from the time location (a time locationat which the second broadcast channel signal is received) of the secondtime-frequency resource location in time domain, to obtain the frameheader location of the radio frame.

Step 709: The terminal device accesses a network based on the frameheader location of the radio frame and system information carried in thesecond broadcast information.

Based on the foregoing embodiments, this application further provides anexample of a physical broadcast channel transmission method, and theexample is applicable to the multi-beam wireless access system shown inFIG. 2 . In this example, a terminal device determines, by using presetscrambling sequences of broadcast channel signals on at least twophysical broadcast channels, that information other than time offsets oftime-frequency resource locations is the same in broadcast informationcarried in the broadcast channel signals of the at least two physicalbroadcast channels. Referring to FIG. 8A and FIG. 8B, a specificprocedure includes the following steps:

Step 801: A base station sends, on a plurality of time-frequencyresource locations in a radio frame, a plurality of synchronizationsignals corresponding to a plurality of physical broadcast channels.

The terminal device receives a first synchronization signalcorresponding to a first physical broadcast channel and a secondsynchronization signal corresponding to a second physical broadcastchannel in the plurality of synchronization signals. The synchronizationsignals are in a one-to-one correspondence with the physical broadcastchannels.

Step 802: The base station performs addition of a CRC, channel coding,scrambling, and modulation on a plurality of pieces of broadcastinformation in a same manner, to generate a plurality of correspondingbroadcast channel signals.

The base station scrambles the plurality of pieces of broadcastinformation by using a plurality of preset scrambling sequences, andsends the plurality of preset scrambling sequences to the terminaldevice.

Step 803: The base station sends the plurality of pieces of broadcastinformation on the plurality of time-frequency resource locations in theradio frame and by using the plurality of physical broadcast channels(in other words, the base station sends the plurality of physicalbroadcast channels). Each piece of broadcast information carriescorresponding broadcast information.

The terminal device receives a first broadcast channel signal on thecorresponding first physical broadcast channel at a first time-frequencyresource location in the radio frame, and receives a second broadcastchannel signal on the corresponding second physical broadcast channel ata second time-frequency resource location.

The first broadcast channel signal carries first broadcast information,the first broadcast information includes a time offset of the firsttime-frequency resource location, the second broadcast channel signalcarries second broadcast information, and the second broadcastinformation includes a time offset of the second time-frequency resourcelocation.

Step 804: The base station determines a first scrambling sequence offirst broadcast channel signal and second scrambling sequence of secondbroadcast channel signal from a plurality of preset scrambling sequencessent by the base station, and determines, based on the first scramblingsequence and the second scrambling sequence, that first information infirst broadcast information is the same as second information in secondbroadcast information.

When determining that the first scrambling sequence is the same as thesecond scrambling sequence, the terminal device determines that thefirst information in the first broadcast information is the same as thesecond information in the second broadcast information.

Step 805: The terminal device determines a time offset differencebetween first time-frequency resource location occupied by firstphysical broadcast channel and second time-frequency resource locationin time domain, obtains a difference sequence corresponding to the timeoffset difference, and generates a scrambling sequence based on thedifference sequence.

The terminal device maintains a correspondence between a time differenceand a difference sequence. Therefore, after obtaining the time offsetdifference, the terminal device may obtain, based on the correspondencebetween a time difference and a difference sequence, the differencesequence corresponding to the time offset difference, to generate thescrambling sequence.

In this example, for a specific process in which the terminal devicegenerates the scrambling sequence based on the difference sequence,refer to the foregoing embodiment. Details are not described hereinagain.

Step 806: The terminal device descrambles the received first broadcastchannel signal based on the scrambling sequence, and descrambles thesecond broadcast channel signal based on a preset second scramblingsequence of the second broadcast channel signal.

The second scrambling sequence is sent by the base station to theterminal device.

In step 806, the terminal device descrambles the first broadcast channelsignal, so that when information carried in the descrambled firstbroadcast channel signal is the same as information carried in thesecond broadcast channel signal descrambled by using the preset secondscrambling sequence, joint decoding is implemented to obtain the secondbroadcast information.

Step 807: The terminal device performs joint decoding on the descrambledfirst broadcast channel signal and the descrambled second broadcastchannel signal, to obtain the second broadcast information.

Step 808: The terminal device obtains a time offset of the secondtime-frequency resource location included in the second broadcastinformation, and determines a frame header location of the radio framebased on a time location of the second time-frequency resource locationin time domain and the time offset of the second time-frequency resourcelocation.

The terminal device subtracts the time offset of the secondtime-frequency resource location from the time location (a time locationat which the second broadcast channel signal is received) of the secondtime-frequency resource location in time domain, to obtain the frameheader location of the radio frame.

Step 809: The terminal device accesses a network based on the frameheader location of the radio frame and system information carried in thesecond broadcast information.

Based on the foregoing embodiments, an embodiment of this applicationprovides a base station, and the base station is applied to themulti-beam wireless access system shown in FIG. 2 , and is configured toimplement the physical broadcast channel sending method shown in FIG. 3. As shown in FIG. 9 , the base station 900 includes a sending unit 901and a processing unit 902.

The sending unit 901 is configured to send at least two physicalbroadcast channels on at least two time-frequency resource locations ina radio frame. One time-frequency resource location is corresponding toone physical broadcast channel, the physical broadcast channel carriesbroadcast information, the broadcast information includes a time offsetof a time-frequency resource location corresponding to the physicalbroadcast channel, the time offset of the time-frequency resourcelocation corresponding to the physical broadcast channel is informationabout a time interval between a time location of the time-frequencyresource location corresponding to the physical broadcast channel intime domain and a frame header location of the radio frame, and timeoffsets of the time-frequency resource locations included in broadcastinformation carried on the at least two physical broadcast channels aredifferent.

The processing unit 902 is configured to generate indication informationfor the at least two physical broadcast channels. The indicationinformation is used to notify a terminal device that information otherthan the time offsets of the time-frequency resource locations is thesame in the broadcast information carried on the at least two physicalbroadcast channels.

The sending unit 901 is further configured to send the indicationinformation.

Optionally, the sending unit 901 is further configured to: send at leasttwo synchronization signals, where any synchronization signal iscorresponding to at least one of the at least two physical broadcastchannels, and synchronization signal sequences carried in the at leasttwo synchronization signals include the indication information of the atleast two physical broadcast channels.

Optionally, the indication information is the synchronization signalsequences carried in the at least two synchronization signals.

Optionally, a difference between a time offset of any one of the atleast two time-frequency resource locations and a time offset of anothertime-frequency resource location is corresponding to one uniquedifference sequence.

Optionally, the processing unit 902 is configured to: before the sendingunit 901 sends the at least two physical broadcast channels on the atleast two time-frequency resource locations, and perform addition of acyclic redundancy check CRC code, channel coding, scrambling, andmodulation in a same manner on the broadcast information carried on theat least two physical broadcast channels, to generate at least twocorresponding broadcast channel signals.

The sending unit 901 is further configured to: send, on each of the atleast two physical broadcast channels, a broadcast channel signalcorresponding to broadcast information carried on the physical broadcastchannel.

By using the base station provided in this embodiment of thisapplication, the base station sends the at least two physical broadcastchannels on the at least two time-frequency resource locations in theradio frame, and sends the indication information for the at least twophysical broadcast channels. In this case, after receiving broadcastchannel signals on two physical broadcast channels, the terminal devicemay determine, based on indication information of the two physicalbroadcast channels, that information other than time offsets oftime-frequency resource locations is the same in broadcast informationcarried in the two broadcast channel signals, to further implement jointdecoding on the two broadcast channel signals, and obtain broadcastinformation carried in one of the broadcast channel signals.

Based on the foregoing embodiments, an embodiment of this applicationprovides a terminal device, and the terminal device is applied to themulti-beam wireless access system shown in FIG. 2 , and is configured toimplement the physical broadcast channel receiving method shown in FIG.5 . As shown in FIG. 10 , the terminal device 1000 includes a receivingunit 1001 and a processing unit 1002.

The receiving unit 1001 is configured to: receive a first broadcastchannel signal on a corresponding first physical broadcast channel at afirst time-frequency resource location in a radio frame, and receive asecond broadcast channel signal on a corresponding second physicalbroadcast channel at a second time-frequency resource location. Thefirst broadcast channel signal carries first broadcast information, thefirst broadcast information includes a time offset of the firsttime-frequency resource location, the second broadcast channel signalcarries second broadcast information, the second broadcast informationincludes a time offset of the second time-frequency resource location,and a time offset of any time-frequency resource location is informationabout a time interval between a time location of the time-frequencyresource location in time domain and a frame header location of theradio frame.

The processing unit 1002 is configured to: determine that firstinformation in the first broadcast information is the same as secondinformation in the second broadcast information, where the firstinformation is information other than the time offset of the firsttime-frequency resource location in the first broadcast information, andthe second information is information other than the time offset of thesecond time-frequency resource location in the second broadcastinformation;

determine a time offset difference between the first time-frequencyresource location and the second time-frequency resource location intime domain;

obtain a difference sequence corresponding to the time offsetdifference, and generate a scrambling sequence based on the differencesequence, where one time offset difference is corresponding to oneunique difference sequence; and

descramble the first broadcast channel signal based on the scramblingsequence, descramble the second broadcast channel signal based on apreset second scrambling sequence of the second broadcast channelsignal, and perform joint decoding on the descrambled first broadcastchannel signal and the descrambled second broadcast channel signal, toobtain the second broadcast information.

Optionally, as for determining that the first information is the same asthe second information, the processing unit 1002 is further configuredto:

obtain indication information of the first physical broadcast channeland the second physical broadcast channel, and determine, based on theindication information, that the first information is the same as thesecond information; or

determine a first scrambling sequence of the first broadcast channelsignal and the second scrambling sequence of the second broadcastchannel signal from a plurality of preset scrambling sequences, anddetermine, based on the first scrambling sequence and the secondscrambling sequence, that the first information is the same as thesecond information.

Optionally, the receiving unit 1001 is further configured to receive afirst synchronization signal corresponding to the first physicalbroadcast channel and a second synchronization signal corresponding tothe second physical broadcast channel; and as for obtaining theindication information, the processing unit 1002 is further configuredto: obtain the indication information included in synchronization signalsequences carried in the first synchronization signal and the secondsynchronization signal.

Optionally, the indication information is the synchronization signalsequences carried in the first synchronization signal and the secondsynchronization signal.

Optionally, as for determining, based on the first scrambling sequenceand the second scrambling sequence, that the first information is thesame as the second information, the processing unit 1002 is furtherconfigured to: when determining that the first scrambling sequence isthe same as the second scrambling sequence, determine that the firstinformation is the same as the second information.

Optionally, the processing unit 1002 is further configured to: afterobtaining the second broadcast information, obtain the time offset ofthe second time-frequency resource location included in the secondbroadcast information; and determine the frame header location of theradio frame based on a time location of the second time-frequencyresource location in time domain and the obtained time offset of thesecond time-frequency resource location.

By using the terminal device provided in this embodiment of thisapplication, the terminal device respectively receives the firstbroadcast channel signal on the corresponding first physical broadcastchannel and the second broadcast channel signal at the firsttime-frequency resource location and the second time-frequency resourcelocation in the at least two time-frequency resource locations. Anybroadcast channel signal carries broadcast information, and thebroadcast information includes a time offset of a correspondingtime-frequency resource location. After determining that the firstinformation (namely, the information other than the time offset of thefirst time-frequency resource location) in the first broadcastinformation is the same as the second information (namely, theinformation other than the time offset of the second time-frequencyresource location) in the second broadcast information, the terminaldevice determines the time offset difference between the foregoing twotime-frequency resource locations, and generates the scrambling sequencebased on the time offset difference. The terminal device may descramblethe first broadcast channel signal based on the scrambling sequence, andimplement joint decoding on the descrambled first broadcast channelsignal and the second broadcast channel signal descrambled based on thepreset second scrambling sequence, to obtain the second broadcastinformation. In this case, the terminal device may obtain accuratebroadcast information, may determine the frame header location of theradio frame based on a time offset of a time-frequency resource locationincluded in the broadcast information, and access a network based on theobtained accurate frame header location of the radio frame and eachpiece of information (such as system information) carried in thebroadcast information.

It should be noted that the unit division in the embodiments of thisapplication is an example, and is merely logical function division.During actual implementation, another division manner may be used.Functional units in the embodiments of this application may beintegrated into one processing unit, or each of the units may existalone physically, or two or more units are integrated into one unit. Theintegrated unit may be implemented in a form of hardware, or may beimplemented in a form of a software functional unit.

When the integrated unit is implemented in the form of a softwarefunctional unit and sold or used as an independent product, theintegrated unit may be stored in a computer-readable storage medium.Based on such an understanding, the technical solutions of thisapplication essentially, or the part contributing to the prior art, orall or some of the technical solutions may be implemented in the form ofa software product. The computer software product is stored in a storagemedium and includes several instructions for instructing a computerdevice (which may be a personal computer, a server, or a network device)or a processor to perform all or some steps of the methods described inthe embodiments of this application. However, the foregoing storagemedium includes any medium that can store program code, such as a USBflash drive, a removable hard disk, a read-only memory (ROM), a randomaccess memory (RAM), a magnetic disk, or an optical disc.

Based on the foregoing embodiments, an embodiment of the presentinvention further provides a base station. The base station is appliedto the multi-beam wireless access system shown in FIG. 2 , is configuredto implement the physical broadcast channel sending method shown in FIG.3 , and has a function of the base station 900 shown in FIG. 9 . Asshown in FIG. 11 , the base station 1100 includes a transceiver 1101, aprocessor 1102, and a bus 1103.

The transceiver 1101 and the processor 1102 are connected to each otherby using the bus 1103. The bus 1103 may be a peripheral componentinterconnect (PCI) bus, an extended industry standard architecture(EISA) bus, or the like. The bus may be classified into an address bus,a data bus, a control bus, and the like. For ease of representation,only one thick line is used for representation in FIG. 11 , but thisdoes not mean that there is only one bus or only one type of bus.

The transceiver 1101 is configured to perform communication interactionwith another device in the multi-beam wireless access system.

The processor 1102 is configured to implement the physical broadcastchannel sending method shown in FIG. 3 , and is further configured to:

send at least two physical broadcast channels on at least twotime-frequency resource locations in a radio frame, where onetime-frequency resource location is corresponding to one physicalbroadcast channel, the physical broadcast channel carries broadcastinformation, the broadcast information includes a time offset of atime-frequency resource location corresponding to the physical broadcastchannel, the time offset of the time-frequency resource locationcorresponding to the physical broadcast channel is information about atime interval between a time location of the time-frequency resourcelocation corresponding to the physical broadcast channel in time domainand a frame header location of the radio frame, and time offsets of thetime-frequency resource locations included in broadcast informationcarried on the at least two physical broadcast channels are different;and

send indication information for the at least two physical broadcastchannels, where the indication information is used to notify a terminaldevice that information other than the time offsets of thetime-frequency resource locations is the same in the broadcastinformation carried on the at least two physical broadcast channels.

Optionally, as for sending the indication information for the at leasttwo physical broadcast channels, the processor 1102 is furtherconfigured to: send at least two synchronization signals, where anysynchronization signal is corresponding to at least one of the at leasttwo physical broadcast channels, and synchronization signal sequencescarried in the at least two synchronization signals include theindication information of the at least two physical broadcast channels.

Optionally, the indication information is the synchronization signalsequences carried in the at least two synchronization signals.

Optionally, a difference between a time offset of any one of the atleast two time-frequency resource locations and a time offset of anothertime-frequency resource location is corresponding to one uniquedifference sequence.

Optionally, as for sending the at least two physical broadcast channelson the at least two time-frequency resource locations in the radioframe, the processor 1102 is further configured to: perform addition ofa cyclic redundancy check CRC code, channel coding, scrambling, andmodulation in a same manner on the broadcast information carried on theat least two physical broadcast channels, to generate at least twocorresponding broadcast channel signals; and send, on each of the atleast two physical broadcast channels, a broadcast channel signalcorresponding to broadcast information carried on the physical broadcastchannel.

The base station 1100 further includes a memory 1104, configured tostore a program and the like. Specifically, the program may includeprogram code, and the program code includes a computer operationinstruction. The memory 1104 may include a random access memory (RAM),and may further include a nonvolatile memory, such as at least onemagnetic disk memory. The processor 1102 executes an application programstored in the memory 1104 and implements the foregoing function, toimplement the physical broadcast channel sending method shown in FIG. 3.

By using the base station provided in this embodiment of thisapplication, the base station sends the at least two physical broadcastchannels on the at least two time-frequency resource locations in theradio frame, and sends the indication information for the at least twophysical broadcast channels. In this case, after receiving broadcastchannel signals on two physical broadcast channels, a terminal devicemay determine, based on indication information of the two physicalbroadcast channels, that information other than time offsets oftime-frequency resource locations is the same in broadcast informationcarried in the two broadcast channel signals, to further implement jointdecoding on the two broadcast channel signals, and obtain broadcastinformation carried in one of the broadcast channel signals.

Based on the foregoing embodiments, an embodiment of the presentinvention further provides a terminal device. The terminal device isapplied to the wireless access system shown in FIG. 2 , is configured toimplement the physical broadcast channel receiving method shown in FIG.5 , and has a function of the terminal device 1000 shown in FIG. 10 . Asshown in FIG. 12 , the terminal device 1200 includes a transceiver 1201,a processor 1202, and a bus 1203.

The transceiver 1201 and the processor 1202 are connected to each otherby using the bus 1203. The bus 1203 may be a peripheral componentinterconnect (PCI) bus, an extended industry standard architecture(EISA) bus, or the like. The bus may be classified into an address bus,a data bus, a control bus, and the like. For ease of representation,only one thick line is used for representation in FIG. 12 , but thisdoes not mean that there is only one bus or only one type of bus.

The transceiver 1201 is configured to perform communication interactionwith another device in the multi-beam wireless access system.

The processor 1202 is configured to implement the physical broadcastchannel receiving method shown in FIG. 5 , and is further configured to:

receive a first broadcast channel signal on a corresponding firstphysical broadcast channel at a first time-frequency resource locationin a radio frame, and receiving a second broadcast channel signal on acorresponding second physical broadcast channel at a secondtime-frequency resource location, where the first broadcast channelsignal carries first broadcast information, the first broadcastinformation includes a time offset of the first time-frequency resourcelocation, the second broadcast channel signal carries second broadcastinformation, the second broadcast information includes a time offset ofthe second time-frequency resource location, and a time offset of anytime-frequency resource location is information about a time intervalbetween a time location of the time-frequency resource location in timedomain and a frame header location of the radio frame;

determine that first information in the first broadcast information isthe same as second information in the second broadcast information,where the first information is information other than the time offset ofthe first time-frequency resource location in the first broadcastinformation, and the second information is information other than thetime offset of the second time-frequency resource location in the secondbroadcast information; determine a time offset difference between thefirst time-frequency resource location and the second time-frequencyresource location in time domain;

obtain a difference sequence corresponding to the time offsetdifference, and generating a scrambling sequence based on the differencesequence, where one time offset difference is corresponding to oneunique difference sequence; and

descramble the first broadcast channel signal based on the scramblingsequence, descrambling the second broadcast channel signal based on apreset second scrambling sequence of the second broadcast channelsignal, and performing joint decoding on the descrambled first broadcastchannel signal and the descrambled second broadcast channel signal, toobtain the second broadcast information.

Optionally, as for determining that the first information is the same asthe second information, the processor 1202 is further configured to:

obtain indication information of the first physical broadcast channeland the second physical broadcast channel, and determine, based on theindication information, that the first information is the same as thesecond information; or

determine a first scrambling sequence of the first broadcast channelsignal and the second scrambling sequence of the second broadcastchannel signal from a plurality of preset scrambling sequences, anddetermine, based on the first scrambling sequence and the secondscrambling sequence, that the first information is the same as thesecond information.

Optionally, as for obtaining the indication information of the firstphysical broadcast channel and the second physical broadcast channel,the processor 1202 is further configured to: receive a firstsynchronization signal corresponding to the first physical broadcastchannel and a second synchronization signal corresponding to the secondphysical broadcast channel; and obtain the indication informationincluded in synchronization signal sequences carried in the firstsynchronization signal and the second synchronization signal.

Optionally, the indication information is the synchronization signalsequences carried in the first synchronization signal and the secondsynchronization signal.

Optionally, as for determining, based on the first scrambling sequenceand the second scrambling sequence, that the first information is thesame as the second information, the processor 1202 is further configuredto: when determining that the first scrambling sequence is the same asthe second scrambling sequence, determine that the first information isthe same as the second information.

Optionally, the processor 1202 is further configured to:

after obtaining the second broadcast information, obtain the time offsetof the second time-frequency resource location included in the secondbroadcast information; and

determine the frame header location of the radio frame based on a timelocation of the second time-frequency resource location in time domainand the obtained time offset of the second time-frequency resourcelocation.

The terminal device 1200 further includes a memory 1204, configured tostore a program and the like. Specifically, the program may includeprogram code, and the program code includes a computer operationinstruction. The memory 1204 may include a random access memory (RAM),and may further include a nonvolatile memory, such as at least onemagnetic disk memory. The processor 1202 executes an application programstored in the memory 1204 and implements the foregoing function, toimplement the physical broadcast channel receiving method shown in FIG.5 .

By using the terminal device provided in this embodiment of thisapplication, the terminal device respectively receives the firstbroadcast channel signal on the corresponding first physical broadcastchannel and the second broadcast channel signal at the firsttime-frequency resource location and the second time-frequency resourcelocation in the at least two time-frequency resource locations. Anybroadcast channel signal carries broadcast information, and thebroadcast information includes a time offset of a correspondingtime-frequency resource location. After determining that the firstinformation (namely, the information other than the time offset of thefirst time-frequency resource location) in the first broadcastinformation is the same as the second information (namely, theinformation other than the time offset of the second time-frequencyresource location) in the second broadcast information, the terminaldevice determines the time offset difference between the foregoing twotime-frequency resource locations, and generates the scrambling sequencebased on the time offset difference. The terminal device may descramblethe first broadcast channel signal based on the scrambling sequence, andimplement joint decoding on the descrambled first broadcast channelsignal and the second broadcast channel signal descrambled based on thepreset second scrambling sequence, to obtain the second broadcastinformation. In this case, the terminal device may obtain accuratebroadcast information, may determine the frame header location of theradio frame based on a time offset of a time-frequency resource locationincluded in the broadcast information, and access a network based on theobtained accurate frame header location of the radio frame and eachpiece of information (such as system information) carried in thebroadcast information.

By using the physical broadcast channel sending/receiving method and theapparatus provided in the embodiments of this application, the basestation in the multi-beam wireless access system sends the at least twophysical broadcast channels on the at least two time-frequency resourcelocations in the radio frame; and the terminal device respectivelyreceives the first broadcast channel signal on the corresponding firstphysical broadcast channel and the second broadcast channel signal atthe first time-frequency resource location and the second time-frequencyresource location in the at least two time-frequency resource locations.Any broadcast channel signal carries broadcast information, and thebroadcast information includes a time offset of a correspondingtime-frequency resource location. After determining that the firstinformation (namely, the information other than the time offset of thefirst time-frequency resource location) in the first broadcastinformation is the same as the second information (namely, theinformation other than the time offset of the second time-frequencyresource location) in the second broadcast information, the terminaldevice determines the time offset difference between the foregoing twotime-frequency resource locations, and generates the scrambling sequencebased on the time offset difference. The terminal device may descramblethe first broadcast channel signal based on the scrambling sequence, andimplement joint decoding on the descrambled first broadcast channelsignal and the second broadcast channel signal descrambled based on thepreset second scrambling sequence, to obtain the second broadcastinformation. In this case, the terminal device may obtain accuratebroadcast information, may determine the frame header location of theradio frame based on a time offset of a time-frequency resource locationincluded in the broadcast information, and access the network based onthe obtained accurate frame header location of the radio frame and eachpiece of information (such as system information) carried in thebroadcast information.

Persons skilled in the art should understand that the embodiments of thepresent invention may be provided as a method, a system, or a computerprogram product. Therefore, the present invention may use a form ofhardware only embodiments, software only embodiments, or embodimentswith a combination of software and hardware. Moreover, the presentinvention may use a form of a computer program product that isimplemented on one or more computer-usable storage media (including butnot limited to a magnetic disk memory, a CD-ROM, and an optical memory)that include computer-usable program code.

The present invention is described with reference to the flowchartsand/or block diagrams of the method, the device (system), and thecomputer program product according to the embodiments of the presentinvention. It should be understood that computer program instructionsmay be used to implement each process and/or each block in theflowcharts and/or the block diagrams and a combination of a processand/or a block in the flowcharts and/or the block diagrams. Thesecomputer program instructions may be provided for a general-purposecomputer, a dedicated computer, an embedded processor, or a processor ofany other programmable data processing device to generate a machine, sothat the instructions executed by a computer or the processor of anyother programmable data processing device generate an apparatus forimplementing a specific function in one or more processes in theflowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may be stored in a computer readablememory that can instruct the computer or any other programmable dataprocessing device to work in a specific manner, so that the instructionsstored in the computer readable memory generate an artifact thatincludes an instruction apparatus. The instruction apparatus implementsa specific function in one or more processes in the flowcharts and/or inone or more blocks in the block diagrams.

These computer program instructions may be loaded onto a computer oranother programmable data processing device, so that a series ofoperations and steps are performed on the computer or the anotherprogrammable device, thereby generating computer-implemented processing.Therefore, the instructions executed on the computer or the anotherprogrammable device provide steps for implementing a specific functionin one or more processes in the flowcharts and/or in one or more blocksin the block diagrams.

Although some embodiments of this application have been described,persons skilled in the art can make changes and modifications to theseembodiments once they learn the basic inventive concept. Therefore, thefollowing claims are intended to be construed as to cover the preferredembodiments and all changes and modifications falling within the scopeof this application.

Obviously, persons skilled in the art can make various modifications andvariations to the embodiments of this application without departing fromthe spirit and scope of the embodiments of this application. Thisapplication is intended to cover these modifications and variationsprovided that they fall within the scope of the claims of thisapplication and their equivalent technologies.

The invention claimed is:
 1. A method comprising: receiving, by aterminal device, a first broadcast channel signal on a first physicalbroadcast channel at a first time-frequency resource location in a radioframe, wherein the first broadcast channel signal carries firstbroadcast information, the first broadcast information comprises firstinformation, and the first information indicates a time offset of thefirst time-frequency resource location; receiving, by the terminaldevice, a second broadcast channel signal on a second physical broadcastchannel at a second time-frequency resource location in the radio frame,wherein the second broadcast channel signal carries second broadcastinformation, the second broadcast information comprises secondinformation, the second information indicates a time offset of thesecond time-frequency resource location; and receiving, by the terminaldevice, an indication, wherein the indication indicates that the firstbroadcast information other than the first information is same as thesecond broadcast information other than the second information.
 2. Themethod according to claim 1, wherein the indication is comprised in asynchronization signal sequence carried in a first synchronizationsignal corresponding to the first physical broadcast channel and carriedin a second synchronization signal corresponding to the second physicalbroadcast channel.
 3. The method according to claim 1, wherein receivingthe indication comprises: receiving, by the terminal device, a firstsynchronization signal corresponding to the first physical broadcastchannel; receiving, by the terminal device, a second synchronizationsignal corresponding to the second physical broadcast channel; anddetermining, by the terminal device according to the firstsynchronization signal and the second synchronization signal, that thefirst broadcast information other than the first information is the sameas the second broadcast information other than the second information.4. The method according to claim 3, wherein the determining comprises:determining, by the terminal device according to a synchronizationsignal sequence carried in the first synchronization signal and thesecond synchronization signal, that the first broadcast informationother than the first information is the same as the second broadcastinformation other than the second information.
 5. The method accordingto claim 1, wherein the time offset of the first time-frequency resourcelocation and the time offset of the second time-frequency resourcelocation are different.
 6. A method comprising: sending, by a networkdevice, a first broadcast channel signal on a first physical broadcastchannel at a first time-frequency resource location in a radio frame,wherein the first broadcast channel signal carries first broadcastinformation, the first broadcast information comprises firstinformation, and the first information indicates a time offset of thefirst time-frequency resource location; sending, by the network device,a second broadcast channel signal on a second physical broadcast channelat a second time-frequency resource location in the radio frame, whereinthe second broadcast channel signal carries second broadcastinformation, the second broadcast information comprises secondinformation, the second information indicates a time offset of thesecond time-frequency resource location; and sending, by the networkdevice, an indication, wherein the indication indicates that the firstbroadcast information other than the first information is same as thesecond broadcast information other than the second information.
 7. Themethod according to claim 6, wherein the indication is comprised in asynchronization signal sequence carried in a first synchronizationsignal corresponding to the first physical broadcast channel and carriedin a second synchronization signal corresponding to the second physicalbroadcast channel.
 8. The method according to claim 6, wherein sendingthe indication comprises: sending, by the network device, a firstsynchronization signal corresponding to the first physical broadcastchannel; and sending, by the network device, a second synchronizationsignal corresponding to the second physical broadcast channel, whereinthe first synchronization signal and the second synchronization signalindicate that the first broadcast information other than the firstinformation is the same as the second broadcast information other thanthe second information.
 9. The method according to claim 8, wherein asynchronization signal sequence carried in the first synchronizationsignal and the second synchronization signal indicates that the firstbroadcast information other than the first information is the same asthe second broadcast information other than the second information. 10.The method according to claim 6, wherein the time offset of the firsttime-frequency resource location and the time offset of the secondtime-frequency resource location are different.
 11. An apparatuscomprising: a non-transitory storage medium including executableinstructions; and a processor; wherein the executable instructions, whenexecuted by the processor, cause the apparatus to: receive a firstbroadcast channel signal on a first physical broadcast channel at afirst time-frequency resource location in a radio frame, wherein thefirst broadcast channel signal carries first broadcast information, thefirst broadcast information comprises first information, and the firstinformation indicates a time offset of the first time-frequency resourcelocation; receive a second broadcast channel signal on a second physicalbroadcast channel at a second time-frequency resource location in theradio frame, wherein the second broadcast channel signal carries secondbroadcast information, the second broadcast information comprises secondinformation, the second information indicates a time offset of thesecond time-frequency resource location, and the first broadcastinformation other than the first information is same as the secondbroadcast information other than the second information; and receive anindication indicating that the first broadcast information other thanthe first information is same as the second broadcast information otherthan the second information.
 12. The apparatus according to claim 11,wherein the indication is comprised in a synchronization signal sequencecarried in a first synchronization signal corresponding to the firstphysical broadcast channel and carried in a second synchronizationsignal corresponding to the second physical broadcast channel.
 13. Theapparatus according to claim 11, wherein the executable instructions,when executed by the processor, further cause the apparatus to: receivea first synchronization signal corresponding to the first physicalbroadcast channel; receive a second synchronization signal correspondingto the second physical broadcast channel; and determine, according tothe first synchronization signal and the second synchronization signal,that the first broadcast information other than the first information isthe same as the second broadcast information other than the secondinformation.
 14. The apparatus according to claim 13, wherein theexecutable instructions, when executed by the processor, further causethe apparatus to: determine, according to a synchronization signalsequence carried in the first synchronization signal and the secondsynchronization signal, that the first broadcast information other thanthe first information is the same as the second broadcast informationother than the second information.
 15. The apparatus according to claim11, wherein the time offset of the first time-frequency resourcelocation and the time offset of the second time-frequency resourcelocation are different.
 16. An apparatus comprising: a non-transitorystorage medium including executable instructions; and a processor;wherein the executable instructions, when executed by the processor,cause the apparatus to: send a first broadcast channel signal on a firstphysical broadcast channel at a first time-frequency resource locationin a radio frame, wherein the first broadcast channel signal carriesfirst broadcast information, the first broadcast information comprisesfirst information, and the first information indicates a time offset ofthe first time-frequency resource location; send a second broadcastchannel signal on a second physical broadcast channel at a secondtime-frequency resource location in the radio frame, wherein the secondbroadcast channel signal carries second broadcast information, thesecond broadcast information comprises second information, the secondinformation indicates a time offset of the second time-frequencyresource location; and send an indication, wherein the indicationindicates that the first broadcast information other than the firstinformation is same as the second broadcast information other than thesecond information.
 17. The apparatus according to claim 16, wherein theindication is comprised in a synchronization signal sequence carried ina first synchronization signal corresponding to the first physicalbroadcast channel and carried in a second synchronization signalcorresponding to the second physical broadcast channel.
 18. Theapparatus according to claim 16, wherein the executable instructions,when executed by the processor, further cause the apparatus to: send afirst synchronization signal corresponding to the first physicalbroadcast channel; and send a second synchronization signalcorresponding to the second physical broadcast channel, wherein thefirst synchronization signal and the second synchronization signalindicate that the first broadcast information other than the firstinformation is the same as the second broadcast information other thanthe second information.
 19. The apparatus according to claim 18, whereina synchronization signal sequence carried in the first synchronizationsignal and the second synchronization signal indicates that the firstbroadcast information other than the first information is the same asthe second broadcast information other than the second information. 20.The apparatus according to claim 16, wherein the time offset of thefirst time-frequency resource location and the time offset of the secondtime-frequency resource location are different.